Universal Bolt Carrier Group with Interchangeable Weights

ABSTRACT

A bolt carrier group includes one or more interchangeable weights that allows the user to control the weight of the bolt carrier group. One or more interchangeable weights are secured inside compartments of the bolt carrier group body such that the weight of the bolt carrier group can be changed depending on desired use of the firearm. The change in weight of the bolt carrier group allows the user to control the recoil of the firearm, the firing rate of the firearm, and the type and caliber ammunition that may be used with the bolt carrier group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/246,212, entitled “Universal Bolt Carrier Group with Interchangeable Weights and filed on Oct. 26, 2015. Such application is incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

BACKGROUND OF THE INVENTION

A bolt carrier group is an assembly that allows a firearm to function by reciprocating back and forth along a track. Generally, the bolt carrier group includes a main body, a bolt, and a firing pin. The bolt holds the cartridge and is the part of the firearm that feeds the cartridge into the chamber for firing. The firing pin causes the cartridge to release from the bolt when the weapon is fired. Once the weapon is fired and the cartridge is released from the bolt, the casing of the cartridge is ejected from the bolt and a new cartridge is chambered. The main body of the bolt carrier group holds the bolt and the firing pin. During the reciprocating movement of the bolt carrier group, the bolt carrier group feeds the ammunition, chambers the ammunition, and then extracts and ejects the ammunition. Thus, the bolt carrier group is responsible for the cocking and the firing mechanisms of the weapon.

The present invention is a technological and engineering innovation which changes the operation and function of firearms and weapons. This invention involves a radical change to the bolt carrier group of a firearm by making the weight of the bolt carrier group adjustable by the end user. This manipulation of the weight of the bolt carrier group of the firearm can help centralize reciprocating mass, slow rate of fire, increase rate of fire, or dampen recoil forces, as described more fully below.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to firearms, and more particularly to a bolt carrier group that can be implemented in a number of different firearms based on its ability to control the weight distribution during the operation of the firearm. It is an object of the present invention to allow the use of different calibers in the same firearm, with the same bolt carrier group. It is also an object of the present invention to allow a firearm user to adjust the operation of the firearm by controlling the weight of the bolt carrier group.

These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description of the preferred embodiments and appended claims in conjunction with drawings as described following.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a left side view of one embodiment of the present invention showing an AR15 or AR10 styled bolt carrier group with the compartment for the interchangeable weight, the interchangeable weight, a threaded end cap, and a set screw to keep the end cap in place.

FIG. 1B is a left side view of one embodiment of the present invention showing an AR15 or AR10 styled bolt carrier group with the interchangeable weight installed.

FIG. 2A is a left side view of one embodiment of the present invention showing an MK17 or other similar style bolt carrier group with multiple compartments for the interchangeable weights.

FIG. 2B is a left side view of one embodiment of the present invention showing an MK17 or other similar style bolt carrier group with the interchangeable weights installed.

FIG. 3A is a left side view of one embodiment of the present invention showing an MK17 or other similar bolt carrier group with a single compartment for the interchangeable weights.

FIG. 3B is a left side view of one embodiment of the present invention showing an MK17 or other similar bolt carrier group with the interchangeable weights installed.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to firearms, and more particularly to a bolt carrier group that can be implemented in a number of different firearms based on its ability to control weight distribution during the operation of the firearm. Generally, the present invention uses removable weighted masses that may be interchanged when different rifle calibers or different strength of cartridges are used. Different types of cartridges expend different amounts of energy when fired. For example, ammunition with a diameter of 7.62 mm and a length of 51 mm and a bullet mass of 175 grains (denoted as 7.62×51 mm 175 gr), the characteristics of one type of commonly used ammunition, expends 3800 joules of energy when fired. The weight of the bolt carrier group and the strength of the recoil spring are two primary elements in the dispersal of the energy expended by firing the projectile. Traditionally, a bolt carrier group is a solid item, with the bolt carrier group having a designated, fixed weight to compensate for the energy of the specific caliber they are designed to work with. The present invention, on the other hand, provides hollow compartments in the bolt carrier group that are capable of receiving interchangeable weights such that the mass of the bolt carrier group can be changed. Because the energy expended by different ammunition affects the bolt carrier group in different ways, the ability to change the weight of the bolt carrier group based on ammunition used allows the user to modify the operation of the firearm. Further, because the weight of the bolt carrier group of the present invention may be changed, the present invention may be used with a number of different calibers while existing bolt carrier groups are limited to use with a single caliber.

The ability to manipulate the weight of the bolt carrier group also allows the user to change the force of the impact of the bolt carrier group's movement in the weapon, because change in the mass of the bolt carrier group changes the overall kinetic energy. This means that the function of the bolt carrier group can be controlled completely by manipulating its operational stroke (i.e. by changing the weight of the bolt carrier group). Changing the weight of the bolt carrier group allows the user to optimize the energy level of the recoil forces depending on the user's needs. This invention helps centralize reciprocating mass, slow rate of fire, increase rate of fire, and dampen recoil forces. While it is understood that the present invention can be implemented in any number of firearm style bolt carrier group assemblies, the present invention is shown as being implemented in AR 15 or AR 10 style firearms and MK17 or other similar style firearms. These examples are non-limiting examples of implementation of the present invention.

With reference to FIGS. 1A-3B, the components of the bolt carrier group of the present invention may be described. The first component of the bolt carrier group 1 is the bolt carrier body 2. The bolt carrier body 2 has hollow compartments 3 such that a weight or weights 4 may be placed inside of the bolt carrier body 2, thus changing the weight of the bolt carrier group 1. As noted above, the present invention may be used in any number of weapon systems and is not limited to the examples provided herein. The bolt carrier body 2 may be a different shape or different style depending on the weapon system used, but the underlying concept remains the same. For example, FIGS. 1A-1B show a bolt carrier group 1 of the present invention for an AR 15 style weapon, while FIGS. 2A-2B and 3A-3B show a bolt carrier group 1 for an MK17 or other similar style bolt carrier. The bolt carrier body 2, regardless of shape or size, may have a compartment or compartments 3 for receiving a weight or weights 4 such that the total weight of the bolt carrier group 1 may be changed. The bolt carrier body 2 may have a single hollow compartment 3 for receiving a single interchangeable weight 4 (see FIG. 1A-1B) or may implement several hollow compartments 3 such that several different weights 4 can be positioned inside of the bolt carrier body 2 such that various total weights of the bolt carrier group 1 can be achieved (as shown in FIG. 2A-2B). The bolt carrier body 2 may also have a single hollow compartment 3 for receiving multiple weights 4 (as shown in FIG. 3A-3B). The removable weights 4 of the present invention attach differently based upon the firearm platform being utilized. For example, in one embodiment the weight or weights 4 may be inserted into a compartment 3 located on the back of the bolt carrier body 2 and may be secured by a threaded cap 5. A set screw may 6 also be used to secure the threaded end cap 5 and weight 4 in place. In another embodiment, the weights 4 may be positioned inside compartments 3 located at the front or middle of the bolt carrier body 2 of the bolt carrier group 1. It is understood that any fastener may be used to secure the weight or weights 4 inside the compartment or compartments 4 of the bolt carrier group assembly 1.

The second component of the bolt carrier group of the present invention is the interchangeable weight or weights 4. As noted above, there may be one compartment 3 for receiving a single interchangeable weight 4, there may be several compartments 3 for receiving several different weights 4, or there may be a single compartment 3 for receiving several different weights 4. Because the potential energy of an object is dependent on the mass of the object and the kinetic energy of an object is directly proportional to the mass of the object and to the square of the velocity of the object, the removable weights 4 function to alter the potential and kinetic energy profiles of the bolt carrier group 1. Kinetic energy, for example, is equal to one half times the mass of the object times the square of the object's velocity. Thus, as the mass (weight) of the object increases, kinetic energy also increases. Likewise, potential energy is calculated by multiplying the mass of the object times the object's acceleration due to gravity (constant) and the height of the object. Thus, as mass increases the potential energy also increases. Thus, an increase in the weight of a bolt carrier group 1 causes an increase in kinetic energy of the bolt carrier group 1 when fired. Differences in the kinetic energy will lead to different amounts of firearm recoil and to different rates of fire. For example, a heavier bolt carrier group 1 will facilitate a slower rate of fire, making the weapon more reliable. A lighter bolt carrier group 1, on the other hand, will increase the rate of fire and will lead to less recoil, but may also cause a decrease in accuracy.

The weights 4 are inserted and secured into the compartments 3 in the bolt carrier body 2 when the user desires a higher weighted bolt carrier group 1. Alternatively, weights 4 may be removed when the user desires a lighter weight bolt carrier group 1. As the weapon fires, the bolt carrier group 1 is pushed to the rear of the weapon along its track. This is performed by a set amount of gas from the weapon discharge that interacts with the bolt carrier group 1 by direct impingement or by contact with a piston. The removable weights 4 of the present invention add to or reduce resistance to the movement of the bolt carrier group 1. This helps slow or accelerate the rearward path of the bolt carrier group 1, which will lead to different firearm operation. For example, slowing the bolt carrier group 1 may be favorable for less motion or a smoother operation of the gun, while a quicker bolt carrier group 1 may be necessary for a higher rate of fire. With each of these benefits of higher and lower weight bolt carrier groups 1 come tradeoffs: for example, a bolt carrier group 1 that travels too slowly will not allow the firearm to cycle properly and one that moves too quickly will expend a greater amount of recoil energy that may lead to higher wear and tear on the gun. Allowing the user to manipulate the weight of the bolt carrier group 1 allows the user to customize the type of operation desired.

Because the purpose of the weighted masses 4 is to change the weight of the bolt carrier group 1, it is preferred that the weights 4 be made with a material with enough mass to have the positive effects on the bolt carrier group 1. It is understood that any suitable metal material may be used, including steel, tungsten, lead, copper, or aluminum. Alternatively, composites and ceramic materials may be used. Furthermore, the present invention may use weights 4 of different masses or different materials such that different effects on the operation of the firearm can be achieved as desired. For example, weight may be added to the bolt carrier group in order to centralize the reciprocating mass of the weapon. The centralization of reciprocating mass requires less force to be applied to the bolt carrier group in order for the bolt carrier group to change direction. Because less force is needed for proper functioning of the bolt carrier group, less recoil force will be transmitted to the shooter, ultimately leading to a more controllable firearm operation.

Alternatively, if the user wants to keep the center of gravity as tight as possible, a heavier or denser material like tungsten may be used. This type of operation may be desired in firearms with a high rate of fire. The center of gravity of an object is the average location of the weight of the object or, in other words, the point where if a force is applied the object moves in the direction of the force without rotation. In firearms, the recoil force as the gun is fired applies a backward force on the firearm which causes it to move reward past the center of gravity. The more weight that is located at the center of the firearm, the less reward movement the recoil forces will create, which means the firearm will ultimately be easier to control and operate. Because the bolt carrier group is typically located at a centralized point on the firearm, altering the weight to the bolt carrier group using an interchangeable weight will keep moving parts closer to the center of gravity, improving control and operation of the firearm.

In yet another example, if the user desires to stabilize the recoiled energy profile, a lighter or less dense metal that takes up more space may be used as the weighted material. Generally, when a weapon is fired, energy is dispersed throughout the gun. An energy profile can be generated and, typically, the energy profile shows a spike in energy because a large amount of energy is dissipated over a short period of time. The use of a weighted material in the bolt carrier group increases the amount of energy necessary to move the bolt carrier group, which creates an increase in drag. This increase in drag creates an extended the time over which the energy is fully dissipated. This leads to a better energy distribution across the entire travel of the bolt carrier group, as the energy profile is less of a spike and more of a wave pattern. This change in energy profile and manipulation of the energy distribution reduces wear on the optics of the firearm and the firearm itself. It is understood that the interchangeable weights may comprise any combination of mass, size, and material such that the operation of the bolt carrier group can be customized based on desired effect.

All terms used herein should be interpreted in the broadest possible manner consistent with the context. When a grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included. When a range is stated herein, the range is intended to include all subranges and individual points within the range. All references cited herein are hereby incorporated by reference to the extent that there is no inconsistency with the disclosure of this specification.

The present invention has been described with reference to certain preferred and alternative embodiments that are intended to be exemplary only and not limiting to the full scope of the present invention. 

We claim:
 1. A bolt carrier group for a weapon comprising: a. a first weighted mass; and b. a bolt carrier group body comprising a first compartment configured to receive the first weighted mass.
 2. The bolt carrier group of claim 1, further comprising a fastener configured to secure the first weighted mass to the bolt carrier group body.
 3. The bolt carrier group of claim 2, wherein the fastener comprises a threaded cap.
 4. The bolt carrier group of claim 1, wherein the first weighted mass comprises a metal material.
 5. The bolt carrier group of claim 1, wherein the first weighted mass comprises a composite material.
 6. The bolt carrier group of claim 1, wherein the first weighted mass comprises a ceramic material.
 7. The bolt carrier group of claim 1, further comprising a second weighted mass and a second compartment configured to receive the second weighted mass.
 8. The bolt carrier group of claim 1, further comprising a third weighted mass and a third compartment configured to receive the third weighted mass. 